Don Pedro Project
Project Operations/Water Balance Model Study Plan
STUDY PLAN W&AR-2
TURLOCK IRRIGATION DISTRICT
AND
MODESTO IRRIGATION DISTRICT
DON PEDRO PROJECT
FERC NO. 2299
Project Operations/Water Balance Model Study Plan
RELICENSING PARTICIPANTS’ COMMENTS
RWG
Meeting
Date
General Comments:
1
08/23/2011
Comment
No.
Comment
2
It was asked that a separate review
session be conducted to cover the
hydrologic data set on inflow to Don
Pedro Reservoir.
In recognition of a recalibration of the
River Temperature Model, and the
development of accretion data for the
river, it was asked that the accretion data
also be reviewed with RPs.
09/15/2011
Section-specific Comments:
3
08/23/2011
Section 5.2. Meeting participants
requested consideration of
disaggregating CCSF upstream
reservoirs to provide additional
hydrologic information concerning
operation of CCFS facilities. It was also
requested to provide the operation of the
CCSF Don Pedro Water Bank Account.
3
08/23/2011
4
09/15/2011
DRAFT-Rev3-09.30.2011
Questions were asked concerning the
model variables that could be controlled
by model users.
RPs asked that Section 5.1 description of
upper boundary of CCSF facilities be
better defined.
Response
See new Section 6.0.
Sections have been revised to recognize
a study plan to recalibrate the River
Temperature Model, and development of
river accretion data with a review of the
work. Section 5.2 describes the
development of an initial report on
accretions, review of the data and
analysis with RPs, and incorporation of
the analysis into the Districts’ modeling
report.
The Districts and CCSF are currently
investigating the feasibility of
incorporating these requests into the
operations model. Additionally,
intermediate river flow nodes between
La Grange Dam and Modesto Gage will
be incorporated into the Operations
Model and the River Temperature
Model.
Section 5.2 refined to better describe the
model variables that will be modifiable
by model users.
Section 5.1 description refined to include
Cherry Valley and Eleanor Dams.
Study Plan W&AR-2 - Page 1
FERC Project No. 2299
Don Pedro Project
Project Operations/Water Balance Model Study Plan
STUDY PLAN W&AR-2
TURLOCK IRRIGATION DISTRICT
AND
MODESTO IRRIGATION DISTRICT
DON PEDRO PROJECT
FERC NO. 2299
Project Operations/Water Balance Model Study Plan
Related Study Requests:
NMFS-04, SWRCB-13
AR-02; Reclamation-02, 04; CDFG-01, LTF-01, NMFS-02,
(See RP General Comment 1)
1.0
Project Nexus
Turlock Irrigation District’s (TID) and the Modesto Irrigation District’s (MID) (collectively, the
Districts) continued operation and maintenance (O&M) of the Don Pedro Project (Project) will
affect reservoir storage levels in Don Pedro Reservoir, reservoir releases, and stream flow in the
Tuolumne River downstream of Don Pedro. This study does not directly address any specific
resource issues, but provides a tool for examining water levels and dam releases under potential
operational scenarios that may inform development of license requirements.
2.0
Resource Agency Management Goals
Several agencies have resource management goals related to reservoir water levels and reservoir
releases. These include the U.S. Army Corps of Engineers (ACOE) for flood management
purposes and reserved flood control storage in Don Pedro Reservoir; the U.S. Department of
Interior (USDOI), Bureau of Land Management (BLM) for public land administered by BLM;
USDOI, Fish and Wildlife Service (USFWS); the State Water Resources Control Board
(SWRCB); and the California Department of Fish and Game (CDFG).
3.0
Study Goals
The study goal is to develop a Project operations computer model (Operations Model) that can
be used by all Relicensing Participants (RPs) to simulate current and potential future operations
of the Project. The objective of the study is to develop an Operations Model that represents the
historical plant operations with reasonable accuracy for purposes of relicensing and can be used
to simulate potential future operations under a variety of operating scenarios.
Study objectives include developing a model that simulates current Project operations for a
period of analysis that covers a range of historical hydrologic conditions. The Operations Model
should also be able to simulate basic decisions made during Project operations including the
DRAFT-Rev3-09.30.2011
Study Plan W&AR-2 - Page 2
FERC Project No. 2299
Don Pedro Project
Project Operations/Water Balance Model Study Plan
management of flood control reservation, water supply management, dam releases, reservoir
levels, and hydropower generation. Objectives also include:
■
reproducing observed reservoir levels, reservoir releases, and hydropower generation,
within acceptable calibration standards over a range of hydrologic conditions,
■
Providing output to inform other studies, analyses, and models,
■
Allowing simulation of changes in Project operations to estimate effects on reservoir
levels, reservoir releases and hydropower generation, and
■
Configuring the model for ease of use by RPs.
4.0
Existing Information and Need for Additional Information
The Districts believe adequate information currently exists to develop the Operations Model that
meets the above objectives. These data are provided in the Pre-Application Document (PAD)
and includes area-storage-elevation information for the Project reservoir, historical operations
data on reservoir water levels, reservoir releases, power generation, and flows downstream of the
Project. The Project’s Flood Control Manual outlines flood control guidelines and objectives.
The existing Federal Energy Regulatory Commission (FERC) license specifies required fishery
releases and flows downstream of the Project. Additional hydrologic data necessary for the
development of Tuolumne River Basin hydrology will be provided by the Districts regarding
operations of CCSF and District Tuolumne River facilities. Hydrologic information used to
develop accretion data for the recalibration of the river temperature model will be provided to the
RPs.
5.0
Study Methods
5.1
Study Area
The study area includes the Tuolumne River from City and County of San Francisco’s (CCSF)
O’Shaughnessy, Cherry Valley, and Eleanor Dams to U.S. Geological Survey Gage 11290000 –
Tuolumne River at Modesto.
5.2
Study Methods
Model development will consist of the following steps:
Step 1 – Model Programming and Data Input for Don Pedro Project Operations Model. The
Districts will utilize Microsoft Excel as the platform to develop the Project Operations Model.
Microsoft Excel is public domain spreadsheet software for personal computers and is readily
available from Microsoft through a variety of sources. There are several advantages to utilizing
a spreadsheet platform for the Operations Model. First, spreadsheets allow transparency in
calculations allowing users to follow and understand the logic. Second, spreadsheets are highly
adaptable, allowing simulation of a wide range of operational criteria, constraints, and
conditions. Third, many Relicensing Participants have some existing level of familiarity with
spreadsheets which can assist in gaining understanding of the model without learning how to
navigate through a new program. Finally, the spreadsheet platform is conducive to allowing
simple data input and result review, including easily applied statistical and graphical outputs.
DRAFT-Rev3-09.30.2011
Study Plan W&AR-2 - Page 3
FERC Project No. 2299
Don Pedro Project
Project Operations/Water Balance Model Study Plan
The Operations Model will be constructed in a spreadsheet program, likely to be greater than 50
megabytes in size. Computation time for the Model will be on the order of seconds to minutes,
depending on computer memory and processor speed, alleviating any need to run only part of the
model or simulation period.
The model will simulate Project Operations for a 40-year period of water years (WY) 1970
through WY 2009 (Period of Record). A water year begins October 1 and ends September 30 of
the following year. For example, WY 1970 begins October 1, 1969 and ends September 30,
1970. The period from WY 1970 through 2009 was selected due to the availability of daily data
at the Project and most stream gaging locations, and depicts the period since the Project was
constructed. The proposed Period of Record includes both the driest (WY 1977) and the wettest
(WY 1983) years for the longer period of available monthly data from WY 1922 through WY
2009, based on the total annual inflow to Don Pedro Reservoir. The period also includes three
multi-year periods of below average inflow; 1976 through 1977, 1987 through 1992, and 2001
through 2004.
The model output would typically be mean daily flow at or below the Project and selected nonProject facilities, daily power production at the Project powerhouse and end-of-day reservoir
elevation. These data can be summarized in a manner most suitable for use in relicensing. For
instance, should agencies and other RPs wish to classify hydrologic conditions by water year
types, this would occur as part of or subsequent to the completion of the analysis. The model
output can be organized by hydrologic conditions or any other proposed grouping.
Table 5.3-1
Model nodes and output for Project and other select locations.
Project Nodes
Model Node
Model Output
Don Pedro Reservoir
Storage and elevation,
regulated and unregulated
inflow
Don Pedro Powerhouse
Don Pedro Dam
Generation, release
through turbine, and
bypass flow
Regulated river release
Nodes Other than Project
Model Node
Model Output
CCSF Upstream
Total inflow, Total
Reservoirs
reservoir storage; San
Joaquin Pipeline
regulated flow, regulated
river release
La Grange Dam
TID and MID Main Canal
Diversions, and river
release
Tuolumne River at
River flow (including
Modesto (Modesto Gage) upstream accretions and
depletions between La
Grange Dam and
Modesto Gage)
(See RP Comment 3)
The model will simulate Project operations at all locations on a daily time-step. In addition, the
model will simulate operation of CCSF (non-Project) facilities above Don Pedro Reservoir, in
aggregate, on a daily time-step. A daily time-step was selected to provide sufficient detail to
address most issues and concerns related to Project operations. A daily time step for the model
has also been selected due to the unavailability and impracticality of data on a sub-daily timestep.
DRAFT-Rev3-09.30.2011
Study Plan W&AR-2 - Page 4
FERC Project No. 2299
Don Pedro Project
Project Operations/Water Balance Model Study Plan
The model will use synthesized mean daily unimpaired flow data developed by the Districts and
the CCSF. Unimpaired flows will be used as inflow to the CCSF reservoirs and the unregulated
portion of inflow to Don Pedro Reservoir in the model. The model will depict the operations of
the CCSF upstream facilities under current requirements, including water demands and
operational policies and agreements, based on CCFS planning studies for the system’s current
configuration. These studies exist for the modeling period 1970 through 2002. Project operation
studies that include 2003 through 2009 will use the historical operation record of CCSF
operations as input to the model. The model will simulate Project reservoir operations to
maintain minimum flow requirements as specified in the existing FERC license. The data and
analysis used to develop the unimpaired flow data set will be provided by an initial report to RPs
for review and comment. One or more workshops (see Section 6) will be convened to discuss the
data and procedures, solicit comments and provide responses. Subsequently the analysis will be
incorporated into the modeling report by the Districts.
Logic to simulate Project operations will be consistent with requirements specified in the ACOE
document entitled “Don Pedro Dam and Lake, Tuolumne River, California; Reservoir
Regulation for Flood Control” dated August 1972 (ACOE 1972). This flood control manual sets
flood control limits in Don Pedro Reservoir for rain flood space from September through May,
and for conditional snowmelt flood space from February through July.
The model will also depict the Districts’ water supply operations through the use of a time series
based on a calculation of current demands, as modeled by current planning studies. As such,
these demands will not be meant to replicate historical diversions and operations, but will
provide a reasonable, systematic depiction of current operations with current demands and
operational requirements.
The model will simulate Project Operations subject to the physical constraints of the Project
including maximum and minimum reservoir capacities, outlets capacities, powerhouse
capacities, and requirements for generation.
Reservoir storage from the previous day will be combined with daily inflows and estimated
demands to make releases from Don Pedro Reservoir according to the following priority:
1.
2.
Minimum flow requirements in the existing FERC license.
Irrigation and M&I water demands within the Districts’ service areas.
Additional releases from Don Pedro will be made to maintain required flood control space per
the flood control manual.
The model will allow the model user to modify flows below La Grange Dam, and model logic
will depict the reaction of Don Pedro Reservoir to any change. Changes in flow requirements
will first operate from Don Pedro Reservoir storage, and if insufficient storage exists, river
releases will reduce the Districts’ canal diversions and if there is still insufficient water, the
model will reduce the requested river flow. The model will also allow user-modification of the
Districts’ canal diversions.
Similar model logic will be provided for the regulated portion of inflow to Don Pedro Reservoir
that occurs as releases from the CCSF upstream system. The model will allow the model user to
DRAFT-Rev3-09.30.2011
Study Plan W&AR-2 - Page 5
FERC Project No. 2299
Don Pedro Project
Project Operations/Water Balance Model Study Plan
adjust regulated releases from the CCSF upstream system which will operate first from CCSF
upstream storage, and if needed from San Joaquin Pipeline diversions.
La Grange Dam will be a model node downstream of the Project. There will be no explicit
operation of the dam and its impoundment except water released from the Project is assumed to
flow into and out of the dam. Diversions into the Districts’ main canals will be simulated based
on the estimated demands. The terminal downstream model node will be the Tuolumne River at
Modesto (Modesto Gage). Accretions and depletions into and out of the Tuolumne River
between La Grange Dam and the Modesto Gage will be estimated for the proposed Period of
Record.
Where intermediate flows below Project facilities are of interest to RPs, as a post-modeling
process, the Districts will calculate mean daily flows at other locations. These locations would
be aligned with locations where the Districts, outside of the Project, may affect flow in the
Tuolumne River, or where estimates of flow can be provided. Flow at these locations will be
estimated by adding the mean daily flow at the Project facility generated by the model and
estimated accretion values calculated at the location. The River Temperature Model will be
recalibrated to a location downstream known as Tuolumne River at Modesto. Accretion data for
intermediate reaches within the model will be developed by the Districts and reviewed with the
RPs (see Section 6).
Step 2 – Develop Water Year Types. Current flow requirements in the FERC license are tied to
the California Department of Water Resources (DWR) San Joaquin Valley Water Year
Hydrologic Classification Indices (60-20-20 Index). The Districts will develop a set of water
year types for use in relicensing, in consultation with RPs. The water year types will be utilized
for potential operational decisions and hydrologic data analysis purposes as part of the
relicensing. These water year types may be based on historical DWR Bulletin 120 forecasts, 6020-20 Index, or other readily available precipitation or meteorological data that is consistently
available to Project operators at the time operational decisions would be made. The Districts will
also include a table presenting the San Joaquin Valley Water Year Hydrologic Classification
Indices and the water year classification presented in the study report for each year simulated in
the model. If another water year type index is recommended, the Districts will also describe the
index or information to be used in determining the different water year type.
Step 3 – Validate the Model. Model validation (i.e., determining that the model is well-founded
and fulfills the purpose for which it was constructed) will occur in four tasks. In the first task,
the Districts will evaluate the model by comparing the model output to the historical record;
specifically, mean daily flows, daily reservoir elevations, mean daily diversions, and total daily
generation over an appropriate, representative period of recent operations (e.g., possibly the
period from WY 1997 through WY 2009). This period provides a wide range of hydrologic
conditions including multiple years of above and below average inflow, years with
comparatively short (WY 1997) and long (WY 2006) duration flood control operations.
Significant differences between historical conditions and model runs will be examined, the
causes identified and documented. It is expected that some differences will occur since it is not
uncommon for change to occur in operating strategy over time, and the differences that exist
between historical daily operations and planning model operations. These differences include the
absence of unplanned outages or operational anomalies that would appear in the historical
DRAFT-Rev3-09.30.2011
Study Plan W&AR-2 - Page 6
FERC Project No. 2299
Don Pedro Project
Project Operations/Water Balance Model Study Plan
operation. Where substantial differences cannot be explained, the model logic/input data will be
adjusted so that the model output estimates better reflect historical values).
In the second task, the Districts will verify that the computer model is a reasonable
representation of the Project’s operating rules. This will be done by making a number of model
runs and reviewing the results with the Districts’ senior staff that have operated the Project. If
the results seem unreasonable, the model logic/input will be examined.
In the third task, the Districts will meet with interested RPs to review the model. This will
include a meeting to generally introduce RPs to the model, including a discussion of the
Districts’ proposed Water Year Types. At that meeting, RPs will be given a CD with an
executable version of the model, a Model Development Report that describes all model input and
logic including priorities, and the Districts’ Draft Model Validation Report. After a reasonable
time for review, the Districts will hold a series of workshops with interested RPs to review the
model.
In the last task, the Districts will finalize the model and the Model Development and Validation
reports, and provide these to RPs. These will also be included in Districts’ application for the
new license.
Step 4: Develop Base Case. The model will be configured to represent how the Districts and
CCSF currently operate their projects, including all physical, regulatory, and contractual
constraints. The underlying assumption is that this base case represents the “No Action
Alternative.” A full description of the Base Case setting will be prepared and distributed. All
subsequent model runs will be compared to the Base Case run.
This study will be considered complete when the model has been developed and validated, and
the Base Case developed. Separate from the study, the Districts’ expert model user will run the
model as reasonably requested by Relicensing Participants. Other interested RPs will make
model runs as they deem appropriate.
6.0
Consultation During Study Implementation
The Districts will conduct a workshop(s) following development of the Don Pedro unimpaired
inflow hydrology and accretion hydrology for the purpose of reviewing and discussing the data
sets and analyses. The Districts will also conduct a workshop when the model is ready for use
and train interested relicensing participants in its use.
7.0
Schedule
The Districts anticipate the schedule to complete the study as follows assuming FERC issues its
Study Plan Determination by December 31, 2011 and the study is not disputed by a mandatory
conditioning agency:
Develop Project Operations Model (Step 1) ....................................................... January-June 2012
Conduct hydrologic data set workshop(s)......................................................................... May 2012
Validate the Model (Steps 2 & 3)
 Task 1 - Calibration/validation and prepare preliminary report ............................ July 2012
DRAFT-Rev3-09.30.2011
Study Plan W&AR-2 - Page 7
FERC Project No. 2299
Don Pedro Project




8.0
Project Operations/Water Balance Model Study Plan
Task 2 - Review operations with the Districts' senior staff .............................. August 2012
Task 3 – Conduct model presentations and
an additional workshops ..................................................... October 2012 - December 2012
Task 4 - Produce final model and report .......................................................... January 2013
Develop Base Case (Step 4)............................................................................... March 2013
Consistency of Methodology with Generally Accepted Scientific Practices
The methods presented in this study plan also are consistent with those used in recent
relicensings in California.
9.0
Deliverables
Products from this study will be the above mentioned model and report.
10.0
Level of Effort and Cost
The Districts will provide an estimate of the cost of this study in the Revised Study Plan.
11.0
References
California Department of Water Resources (DWR). 1970-2009. Water Conditions in California:
Bulletin 120. Sacramento, California. Published four times annually: February, March,
April, May. Available at: http://cdec.water.ca.gov/snow/bulletin120/.
United States Army Corps of Engineers (ACOE). 1972. Don Pedro Lake, Tuolumne River,
California; Reservoir Regulation for Flood Control. Sacramento District, Sacramento,
CA. August 1972.
United States Geological Survey (USGS). 1970-2009. USGS Water Data for the Nation, various
stations for the Tuolumne River Basin. Available at: http://waterdata.usgs.gov/nwis/
City and County of San Francisco (CCSF). 1983-2007. Various hydrologic data for the
Tuolumne River Basin. Available at: http://www.donpedrorelicensing.com/documents.aspx
DRAFT-Rev3-09.30.2011
Study Plan W&AR-2 - Page 8
FERC Project No. 2299